[nmarriott]

No, this is not how it works. There is no terminal emulator that offers this kind of fine-grained mouse support. tmux can either turn the mouse on and handle everything (resize, scroll, copy and paste) itself, or it can leave it off and receive no mouse events.

[enriquto]

Then it could react to a middle-click inside a pane by pasting the text of the clipboard.

[nmarriott]

tmux has no direct access to the X clipboard itself. Reading the clipboard with OSC 52 is possible but it is unfortunately not widely supported by terminal emulators (you can do it with `refresh-client -l` if the terminal emulator supports it).

Or you could read it with `xclip`, `xsel` or `pbpaste`, something like:

    bind -n MouseDown2Pane run "pbpaste|tmux loadb -" \; pasteb

From tmux 3.2, middle click will paste the top tmux paste buffer by default.